In the case of transmitting a digital signal via a transmission line, there is a problem that, on the reception side, due to reflection of a part of signal energy at a timing that a signal level changes, a waveform distortion such as overshoot or undershoot, that is, ringing occurs.
For example, as a ringing suppression circuit suppressing ringing which occurs in a differential signal transmitted in a transmission line, a ringing suppression circuit operated by power source voltage supplied (hereinbelow, a power-source-necessary suppression circuit) is provided.
For example, as a ringing suppression circuit, a ringing suppression circuit (hereinbelow, a power-source-unnecessary suppression circuit) operated by voltage between a pair of signal lines constructing a transmission line without power source voltage supplied is provided.